Upon the murder of King Gagik II, Constantine’s father gathered his family and fled to the Taurus Mountains and took refuge in the fortress of Kopitar (Kosidar) situated north of Sis (today Kozan in Turkey).[1] As Roupen was growing old by 1090, his command seems to have passed entirely to Constantine; and it was the latter who in the same year conquered the strategic Cilician castle of Vahka (today Feke in Turkey).[1] The mastery of this mountain defile made possible the assessment of taxes on merchandise transported from the port of Ayas towards the central part of Asia Minor, a source of wealth to which the Roupenians owed their power.[4]

After his father’s death in 1095, Constantine extended his power eastward towards the Anti-Taurus Mountains.[2] As an Armenian Christian ruler in the Levant, he helped the forces of the First Crusade maintain the siege of Antioch until it fell to the crusaders.[1] The crusaders, for their part, duly appreciated the aid of their Armenian allies: Constantin was honored with the titles of Comes and Baron.[4]

The Chronographie of Samuel of Ani records that Constantine died soon after a lightning bolt struck his table in the fortress of Vahka.[3] He was buried in Castalon.[1]